1. Field of the Invention
The present invention relates to an object taking-out apparatus for taking out an object using a robot hand, and more particularly, to an object taking-out apparatus provided with object holding means whose orientation is changeable according to condition placement of an object.
2. Description of Related Art
Recently, robots have been made more intelligent to perform operations on objects. For example, an operation of taking out objects randomly stacked in a container or on a pallet is a typical application of a robot having a hand attached to an arm end. For taking out the objects randomly stacked and not subjected to positioning, the position/orientation of each individual object is detected by means of a visual sensor or the like, and according to the detected result, the operating position/orientation of the robot is determined before taking out objects.
In taking out objects randomly stacked in a container, both the robot arm and the robot hand should not interfere with the container. This usually imposes limitations on taking out of objects. Specifically, objects that can be taken out without causing interaction are limited to those adequately spaced away from the peripheral wall of the container and not tilting toward the container wall. These requirements make it difficult to remove all the objects from the container.
To avoid the interaction problem, an interaction avoiding apparatus is proposed for example in JP 2002-331480A, which operates to actively change the orientation of the robot arm and the rotary position of the robot wrist, so that they do not enter a preset interaction region, thereby avoiding the interaction between the container and the robot arm or hand. However, this kind of prior art still cannot remove objects placed near or tilting toward the container wall and objects surrounded by other objects highly stacked around them.